Prime Products 12-4058 AC Power Line Monitor (788530)

Summit: I use this when I test my house generator as well as with my RV etc. Around the house, you can use it to check for missing grounds at outlets (if you have an older house, you may be surprised how many).
Great, useful tool for anyone with a generator or doing some outlet repairs/upgrades.

United States on Jan 07, 2017

Mrfixit: We purchased this for a RV. Well made and very easy to use. Also checked out all the outlets in our house. When using this in motor home will determine if there is a problem within the power pedestal. Its pretty straight forward and always displays the AC voltage coming in on the power line. This way its easy to keep a eye on the power if it fluctuates.
Would definitely purchase this again. I can't think of anything else unless it offered a complete surge protection. But hardly at this price of $30.00 + or -.

United States on Oct 30, 2015

LSU Tigee: After experiencing blown breakers in out travel trailer I started researching possible issues. One statement was repeated over and over in each forum thread "get a line voltage monitor". I bought this and it works great. Just used it for the first time and we were able to see the drop in voltage as were turned on the A/C or microwave. We saw drops and fluctuations through out the day, sitting at 120 with no A/C on and seeing it drop to 116 when it kicked on. We only blew a breaker once when I forgot to turn off the A/C and ran the microwave. so running the fridge/water heater/A/C was fine and we fluctuated between 112 to 117 most of the time turning on the MW with everything else on blew the main inside the trailer most of the time. We were able to make a habit of looking at the meter though out the day to keep tabs on the voltage

United States on Jun 18, 2013

Charles W.: I bought this to monitor the AC Voltage from my generator. As a plus it also detectes if the ac outlet is wired correctly. I was initially worried if the display was full sized or not - It is. The only negative about the device is that it's bigger and heavier than you might prefer to keep in your tool box. Working from memory, it's about 3" W x 4" H x 2" T. I think that's kind of big for what it does.

On the other hand it does seem to work just fine. I've had it plugged into the AC power in my bedroom for about a week now and it is still working fine. I can see the line Voltage occasionally go up or down by about a Volt.

United States on Sep 23, 2011

DM: I bought this to use in my travel trailer after recently discovering that many parks don't supply adequate voltage at the power pedestal and there can be polarity issues as well. It's very well suited for this. The display doesn't display voltage with a decimal but it does show voltage in rounded numbers, which is more than adequate for my use. I checked it against an expensive digital meter and it displayed the correct voltage during testing. It appears to round up at .5 and above. The polarity check feature is an important feature, especially when using electricity at camp sites.
This is a great solution if you want to easily and quickly check polarity and have a more accurate voltage reading than an analog meter can supply, not to mention that it doesn't cost much more than a good analog meter.
The price and simplicity makes this a great product along with the fact that it reports two very important things. I rated this product with five stars because it does what it says and is a good product for the money. I will update this review after using the product for a few months if I find an update is necessary.

United States on Sep 17, 2011